This article describes creating services for Windows Mobile 2003 Software for Pocket PCs and how to shape existing background applications into services that run in one process as different threads.

We strongly recommend using services for background tasks because of the 32 processes limit imposed by Windows CE. Pocket PC 2000 and Pocket PC 2002 do not implement services.exe process but there is a way to use your services on those devices as well.

So I strongly recommend every developer should give this article a read and follow the suggestions made there.